1. Field of the Invention
The present invention relates to a keypad assembly for a portable radiotelephone, and more particularly, to a keypad assembly for a portable radiotelephone wherein a keypad can also be used as a touch screen panel, and a method of controlling the same.
2. Description of the Prior Art
Recently, owing to the development of the electronic communication industry, mobile radio communication equipment such as cellular phones, PDAs, and portable PCs have been rapidly developed to transmit or receive data and to use content in various multimedia environments. In particular, in the portable radiotelephone widely known as cellular phone, the display device has been widened in many models for the user's convenient carrying and the accommodation of various functions. It has also been found that a keypad assembly used as a key input means can accommodate various functions through a mode shift.
A portable radiotelephone can employ a touch screen mode or a keypad assembly as the key input means for inputting data or the telephone numbers of other parties. In particular, the keypad assembly employs a method of applying a signal, wherein the bosses, which are formed under the keypad rubber with a plurality of key buttons integrally formed, press the metal domes mounted on the printed circuit board of the body. The metal domes are then electrically contacted with the carbon contacts of the printed circuit board.
In a method wherein the touch screen mode is employed instead of the keypad assembly, a user employs input means such as a stylus pen.
The convenience of using a radiotelephone is furthered by employing the keypad assembly and simultaneously employing a display for a touch screen.
Recently, in some models of radiotelephone, a dummy keypad with a keypad printed thereon has been hingedly installed between body and folder or between body and flip, while the above touch screen mode has been left unchanged. When using the dummy keypad of the radiotelephone, the dummy keypad is laid on the touch screen, and then the numeral buttons are pressed. Thus, the inconvenience of manipulating a stylus pen to use the touch screen can be avoided.
As described above, however, in the case of using a touch screen which does not occupy the body of the radiotelephone, there may be the inconvenience of using a stylus pen. Further, in the case of using the dummy keypad, the radiotelephone is thickened by the thickness of the dummy keypad, which is contrary to the beneficial trend towards thinner and lighter radiotelephones. Also, in the case of using the dummy keypad, there is a problem of moving the dummy keypad to the display.